/**
 * Initialize app telemetry. Opt-in via `NODE_OTEL_ENABLED`; a no-op otherwise.
 * Idempotent and defensive: if the OTel packages are absent or fail to load,
 * the SDK silently stays a no-op rather than breaking the app.
 */
export declare function initAppTelemetry(appName: string): Promise<void>;
/** True once telemetry is live (opt-in + successfully initialized). */
export declare function telemetryActive(): boolean;
/**
 * Increment a named counter by `value` (default 1), tagged with `attributes`.
 * A no-op when telemetry is inactive, so hot paths can call it unconditionally.
 */
export declare function incrementCounter(name: string, value?: number, attributes?: Record<string, string | number | boolean>): void;
/**
 * Inject the active trace context into `carrier` for cross-IPC propagation.
 * No-op (returns the carrier unchanged) when telemetry is inactive.
 */
export declare function injectTraceContext(carrier: Record<string, string>): Record<string, string>;
/**
 * Run `fn` within the trace context extracted from `carrier`, inside a SERVER
 * span named for the capability. When telemetry is inactive this just runs
 * `fn` directly with no overhead.
 */
export declare function traceIncomingCapability<T>(capability: string, carrier: Record<string, string> | undefined, fn: () => Promise<T>): Promise<T>;